Two protection-inducing antigens specific to the L1 larva of Trichinella spiralis will be investigated regarding their structure and function using immunological, biochemical and molecular biological approaches. Expression and genomic libraries in suitable vectors will be constructed and cloned DNA molecules encoding both the 48K and 50/55K protein will be isolated. Expression of positive cDNA clones will be identified by colony immune assay with polyvalent rabbit anti-48K and 50/55K antibodies. Fusion peptides containing epitopes will be tested for their ability to induce protection in mice. Southern blot analysis will determine the genomic arrangement of DNA encoding both antigens. Northern analysis on each stage of Trichinella spiralis (L1-L4 larva, adult and newborn larva) will reveal the stage- specificity of gene expression for each antigen. The sequence of cDNA and genomic DNA for each antigen will be determined. Both proteins can be phosphorylated, and in addition, the 48K antigen binds divalent cations, particularly Ca2+. Thus peptide mapping and sequencing studies on each molecule will be carried out to determine the sites of phosphorylation for both proteins, and the number and sites of Ca2+ binding for the 48K molecule. Computer analysis of the primary amino acid consensus sequence and DNA sequence will determine areas of hydrophobicity and degrees of homology with other known sequences. Particular attention to similarities between regulatory proteins and the 48K and 50/55K antigens will be given, since preliminary data indicate that they may be involved in regulation of host anerobic glycolysis.